I am interested in using the EVALZ-AD8253 evaluation board to amplify a 150kHz 200mVpp AC signal upto a 150kHz 20Vpp signal. I am finding that the output signal has an extremely large DC voltage offset on the order of many volts (seemingly beyond the power that is being provided to the board). The signal initially looks like what I want, but the DC offset drifts down within a few seconds to the point where the output is just a DC signal at the negative power supply voltage (-15V). I have attached an image of a few snippets of what the signal looks like over the course of a few seconds, along with my bench setup with connections.
I am supplying the board with +-15V and it draws between 10mA and 20mA. I noticed that the power usage is typically lower on the negative supply. The signal I am inputting is two ~140mVpp signals 90 degrees out of phase with a gain of 100. This outputs a clean 150kHz 20Vpp signal before it drifts off. I also tried using different gains, lower frequency and lower amplitude (two 10mVpp inputs at 150kHz) but the problem still persists. No components on the board seem to be unusually hot either.
Is there an issue with the way I am using the board, or does this sound like a faulty board?
Added that no components are heating up alot.
[edited by: sampa at 3:15 PM (GMT -4) on 21 Aug 2024]
